It has long been recognized that internal combustion engines, and particularly those in use in motor vehicles are a major source of atmospheric pollution. Government regulations have thus been put in place in many countries to force motor vehicle manufacturers to devise ways of reducing the amount of pollutants being emitted by motor vehicles. The current solution generally adopted by motor vehicle manufacturers is to pass the engine exhaust stream through a catalytic converter to reduce or eliminate by oxidation and reduction various of the pollutants in the exhaust stream.
As is well known, noise mufflers are a standard part of a motor vehicle exhaust system.
Catalytic converters have generally been positioned in the exhaust system as a separate unit between the engine exhaust manifold and the muffler.
This arrangement has been generally satisfactory to accomplish the pollutant reduction function. However, it has lead to a number of subsidiary problems. The most serious of these is that the catalytic converter unit can be removed by any person with reasonable mechanical skills and replaced by a straight and unrestricted exhaust pipe section. Because of the expense in replacing the catalytic converter when an original unit is for one reason or another no longer useable, this replacement by a straight through section of exhaust pipe has frequently been adopted. This substitution obviously completely defeats the objective of the catalytic converter, pollution control.
The present invention eliminates this removal problem by combining in a single unit the catalytic converter and the muffler.
While the above discussion has related to problems with the catalytic converter, motor vehicle mufflers have also presented problems. A major one of these is that mufflers are prone to rust out partly as a result of condensation within the muffler after the engine has been shut down. The present invention reduces this condensation and thus can contribute to extended muffler life.